THIS invention relates to a method of operating a network, typically a packet radio network, which comprises a network operator station and a plurality of user stations.
A network of this general kind is described in PCT patent application no. WO 96/19887 and comprises a plurality of stations which monitor each other's activity and transmit message data to one another, either directly or via intermediate stations, in an opportunistic manner. One or more of the stations can function as a network operator station which regulates the access of other stations to the network and thus to desired destination stations.
In a commercial implementation of such a network it is necessary to uniquely identify each station and to control its access to the network, both for security and billing purposes. This will prevent, for example, continued use of the network by a subscriber whose account has fallen into arrears, and the interception of messages by an unauthorised station.
The different stations may communicate via the same or different media. The principle by which the stations generate their routing information is by detecting other stations in their immediate vicinity, and monitoring the data these stations send. By monitoring the contents of the data, a station will be able to dynamically find routes to other stations in the network. This will allow a station to send data to any other station, via any intermediate station, in the network even though it can not directly communicate with the destination station.
If someone were to place an unauthorised station in the network, with an ID that belonged to another station, it would cause routing problems and allow the unauthorised station to intercept the data. Therefore it would be necessary to make sure that no unauthorised station could cause legitimate stations to send it any data, and to ensure that a transmission from the unauthorised station does not interfere with the dynamic routing tables in the legitimate stations.